Vitamin and Mineral Nutrition Information System (VMNIS)

Key to the data tables for the Database on Iodine Deficiency

The most recent survey information for each country is displayed at the top of the data tables, followed by earlier surveys if available. Within each survey, the data of the total population surveyed (Total) is displayed first. Disaggregated data are displayed thereafter by sex, age, region or other suitable criteria. For surveys reporting on goitre prevalence and urinary iodine, goitre prevalence is displayed on top followed by urinary iodine. An empty field means that no data have been reported. If no cases were found 0 is inserted.


The following abbreviations are used to describe survey administrative levels:

N = National
R = Regional
S = State
D = District
L = Local

Surveys carried out exclusively in urban and rural areas are specified by adding a U or R to the administrative level. For example NU stands for National Urban.

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The date field reflects the year(s) during which the survey took place. If no date was given for the survey, the date of publication is used and a P is inserted next to the date, for example, 1999 P.

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Region and sample descriptor

This field describes the location of the survey and the sample itself, that is, the specific population surveyed.

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The sex of the population surveyed. If no sex is stipulated, it is assumed that both sexes were studied.

B = Both
F = Females
M = Males

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The age of the population surveyed expressed in years.

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Sample size

The sample size of population investigated. The abbreviation NS (not specified) is used when the sample size is not provided in the survey report.

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Goitre prevalence

The prevalence (%) of the population surveyed with a palpable goitre classified as follows.

  • Grade 1: A goitre that is palpable but not visible when the neck is in the normal position, even when the thyroid is not visibly enlarged. Thyroid nodules in a thyroid, which is otherwise not enlarged, fall into this category.

  • Grade 2: A swelling in the neck that is clearly visible when the neck is in a normal position and is consistent with an enlarged thyroid when the neck is palpated.

  • TGP: Total goitre prevalence: Grade 1 + Grade 2

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Urinary iodine (µg/L)

Urinary iodine results expressed in terms of µg/dL or µmol/L have been converted to µg/L. Data expressed in µg/g creatinine and µg/24h are reported in the line notes.

  • Distribution (%): The percentage of the population surveyed falling within the categories < 20 µg/L, 20-49 µg/L, 50-99 µg/L, 100-299 µg/L, > 300 µg/L .

  • Prevalence (%): The percentage of the population surveyed falling below the cut off level of 100 µg/L.

  • Median/mean/SD: Median and/or mean and standard deviation (SD) of urinary iodine (µg/L)

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References for each country are shown at the bottom of the data table categorized as:

  • Data references: references for which data are presented.
  • Additional references: references providing additional information on iodine deficiency disorders for the country in question.
Letters following the reference numbers refer to different surveys within the same reference.

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General notes

An asterisk (*) indicates that a general note, that is additional information applying to the entire survey (for example details on the survey design) is provided at the bottom of the data tables.

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Line notes

These notes provide additional information to the data found in a specific line. Details are given at the bottom of the data tables.

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Abbreviations used

The following abbreviations were used in the "Location and sample descriptor", "General notes" or "Line notes" columns:

CI = Confidence interval
LW = Lactating women
NPNL = Non-pregnant, non-lactating women
NPW = Non-pregnant women
Pre-SAC = Pre school-age children
PPS = Probability proportionate to size
PW = Pregnant women
SAC = School-age children
SD = Standard deviation
TGP = Total goitre prevalence
UI = Urinary iodine